A lone cyclist navigates the bike path through a snow storm at Chicago's North Ave. beach Thursday, Dec. 27, 2012. A muted version of the deadly winter storm that has killed more than a dozen across the eastern half of the country reached the Northeast on Thursday, limiting most of its wrath to travel headaches as Christmas revelers tried to return home. (AP Photo/Charles Rex Arbogast)

DENVER - A storm that has dumped more than a foot of snow in the Rocky Mountains was causing problems for travellers as it spread across the Plains on Wednesday.

The main east-west route across Colorado, Interstate 70, closed for several hours from east of Denver to the Kansas line because of poor visibility due to blowing snow. Eastbound lanes remained closed Wednesday night. Smaller highways were also closed for hours in eastern Colorado.

Drivers in Iowa and Nebraska are being warned to be careful or stop driving altogether starting Wednesday evening as the Plains gets its first major winter storm of the season.

Light snow is also expected at Chicago's O'Hare International Airport on Thursday and strong winds could make visibility poor. That, combined with low clouds, could cause delays at the nation's second-busiest airport. National Weather Service forecaster Jamie Enderlen said.

Iowa officials advised drivers to avoid most roads from Wednesday night through noon Thursday, but native Laurie Harry, a manager at a Casey's General Store, expects to drive to work Thursday morning.

"If I need to get into work, I'll be here," she said. "We've had snow before. Iowans know what to expect. We're used to it."

Conditions improved in Denver by midday Wednesday. At the height of the storm, Denver's airport, the nation's fifth-busiest, reported delays averaging 30 minutes because of snow and ice, but operations have since returned to normal.

Delta and United Airlines reacted by announcing plans to allow many affected travellers across the nation to change schedules without incurring fees.

The snow is a gift for ski resorts in Arizona, Colorado, New Mexico, and Utah ahead of the busy holiday week. The weather might also tempt backcountry skiers but prompted avalanche warnings in Colorado and Utah.

Colorado officials near Vail, about 90 miles west of Denver, planned to trigger some small snow slides in order to remove larger threats.

In Utah, a backcountry skier triggered a slide near a Park City ski resort. Authorities said no one was injured.

In Nebraska, officials have closed parts of Interstate 80 in the western and south central parts of the state. Nebraska State Patrol Deb Collins said one vehicle fatality was reported near North Platte and there were reports of numerous car accidents and slide offs.

The moisture is also a relief after an extended wildfire season in Colorado. Drought conditions persist especially in the mainly agricultural eastern half of the state.

Farmer Fred Midcap welcomed the snow even though 25 mph winds were blowing some of it away from his land near Hudson in northeastern Colorado.

"The snowflakes are mostly going sideways," he said.

Midcap doesn't plow his land, a move intended to help improve the soil, and said the stubble leftover from this year's weak millet crop will help hold some of the snow in place, hopefully setting up for a better growing season next year. If the snow keeps coming, it will also provide some welcome insulation to his winter wheat crop before the coldest weather of the season.

In Arizona, two recent storms had combined to blanket the mountains north of Flagstaff with 2 feet of snow, and about 20 inches in Flagstaff and along the Mogollon Rim.

The storm is also expected to hit Wisconsin and Michigan, where up to a foot of snow was forecast in the north by Friday.